This invention relates generally to electronic transaction systems and, more particularly, to portable electronic transaction devices and associated terminals therefor.
Recent years have seen the rapid growth in the number and types of devices carried by the user and employed for credit card, location access, facility access, bank tellering or guard routing purposes. Such devices will hereinafter be referred to by the generic term "transaction devices" to signify the use of these devices as a means for effecting a transaction, such as a credit card sale, a bank deposit, access authorization, etc.
Prior art transaction devices have recently made use of a card or other compact structure for carrying information thereon and which is arranged to be inserted into a terminal to transfer information thereto. With the advent of micro-chip technology, some transaction devices have now incorporated electronic circuitry to store, transmit and receive various information such as identifier information, transaction and status information. Thus, the transaction device itself only forms one portion of what can be called a transaction system. That system can include various independent terminals, which may include their own intelligence (via the use of microcomputers therein) or may be interconnected to a remote or host computer (e.g., a main frame computer) via telephone lines or other data transmission equipment.
As is known, the availability and proliferation of low-cost, powerful microcomputers has resulted in increasing numbers of unauthorized intrusions into computer-based systems by criminals as well as pranksters. Thus, the newly developing transaction devices are susceptible to attacks on the security in the systems using them. For example, existing transaction devices frequently make use of mechanical, e.g., metal, contacts for connection to the terminal or system. While such means are simple in construction and relatively low in cost, they offer a readily accessible means for connection with an intruder's microcomputer to read the information in the transaction device or otherwise use it. Such action can be readily effected by cycling the microcomputer through various possible identifier codes to gain access to the system and its data. A further problem with transaction devices employing metal electrical contacts as the means for connection into the system is the tendency of such contacts to oxidize or be susceptible to physical damage. Either of these occurrences can reduce the reliability of electrical continuity and hence, data transfer.
Other prior art transaction devices have utilized capacitance means encapsulated in a card for the storage of information therein. Such capacitance-based devices are also susceptible to unauthorized access through the use of various means, such as capacitance bridges. Still other electronic transaction systems have made use of magnetic strips, such as on conventional plastic credit cards, for carrying information. Needless to say, the latter type of transaction device offers a very low degree of security inasmuch as the magnetically stored data can be readily read and duplicated with existing equipment.
A further security problem with prior art transaction devices is that they transmit information between the components of the entire system in an unencrypted or "clear" form, e.g., standard ASCII symbols, etc. The transmitted data, e.g., the bit stream, can therefore be easily read to determine identifier codes and other internal security information necessary for access to the system. Thus, once identifier codes, communication formats, and other system protocols are determined, the portable transaction device can be duplicated or forged, or the system can be entered at the terminal without a valid device.
Needless to say, the unauthorized or improper use of transaction systems can result in the losses of millions, if not billions, of dollars and serious breaches in high security systems.
An additional drawback of existing portable transaction devices is the fact that such devices do not have stand-alone capability. That is, they are constructed to be inactive (inoperative) when they are not connected in the system, e.g., not inserted in the terminal. Therefore, attempts at physical intrusion into the devices such as by delamination of the material encasing the device (e.g., "credit card" type), or inoperative conditions in the device as a result of an internal failure cannot be detected during the "off" or inactive period.
Examples of prior art transaction devices are shown in the following U.S. Pat. Nos. 3,637,994 (Ellingboe), 3,934,122 (Riccitelli), 3,702,464 (Castrucci), 3,868,057 (Chavez), 3,876,865 (Bliss), and 4,001,550 (Schatz) and 4,211,919 (Ugon). The aforegoing devices exhibit one or more of the characteristics as described heretofore, e.g., the employment of metallic electrical contacts, the use of clear (non-encrypted) communication and the failure to incorporate any stand-alone capability. U.S. Pat. No. 3,906,460 (Halper) discloses a transaction device using inductive coupling for communication, yet has no stand-alone, encryption or data processing capabilities. The devices disclosed in U.S. Pat. Nos. 3,971,916 (Moreno), 4,092,526 (Moreno), and 4,102,493 (Moreno), employ either mechanical or optical coupling for communications, thereby eliminating the problems inherent in the use of mechanical electrical contact. However, such devices have no stand-alone or encryption capability and are hence susceptible to intrusion.
Articles about credit card type transaction devices have recently appeared in the following publications: Byte magazine, January 1984, pages 154-168, and IEEE Spectrum, February 1984, pages 43-49.